doc: Reorder and clarify contributing instructions.

* doc/contributing.texi (Building from Git, Running Guix Before It Is
Installed): Make instructions using Guix come first and clarify which code is
an instruction and which is merely an example.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

1 files changed, 19 insertions, 17 deletions

diff --git a/doc/contributing.texi b/doc/contributing.texi
index 7f2301409a..59917193f1 100644
--- a/doc/contributing.texi
+++ b/doc/contributing.texi
@@ -38,19 +38,6 @@ version from the Git repository:
 git clone https://git.savannah.gnu.org/git/guix.git
 @end example
 
-When building Guix from a checkout,
-the following packages are required in addition to those mentioned in
-the installation instructions (@pxref{Requirements}).
-
-@itemize
-@item @url{http://gnu.org/software/autoconf/, GNU Autoconf};
-@item @url{http://gnu.org/software/automake/, GNU Automake};
-@item @url{http://gnu.org/software/gettext/, GNU Gettext};
-@item @url{http://gnu.org/software/texinfo/, GNU Texinfo};
-@item @url{http://www.graphviz.org/, Graphviz};
-@item @url{http://www.gnu.org/software/help2man/, GNU Help2man (optional)}.
-@end itemize
-
 The easiest way to set up a development environment for Guix is, of
 course, by using Guix!  The following command starts a new shell where
 all the dependencies and appropriate environment variables are set up to
@@ -61,7 +48,22 @@ guix environment guix --pure
 @end example
 
 @xref{Invoking guix environment}, for more information on that command.
-Extra dependencies can be added with @option{--ad-hoc}:
+
+If you are unable to use Guix when building Guix from a checkout, the
+following are the required packages in addition to those mentioned in the
+installation instructions (@pxref{Requirements}).
+
+@itemize
+@item @url{http://gnu.org/software/autoconf/, GNU Autoconf};
+@item @url{http://gnu.org/software/automake/, GNU Automake};
+@item @url{http://gnu.org/software/gettext/, GNU Gettext};
+@item @url{http://gnu.org/software/texinfo/, GNU Texinfo};
+@item @url{http://www.graphviz.org/, Graphviz};
+@item @url{http://www.gnu.org/software/help2man/, GNU Help2man (optional)}.
+@end itemize
+
+On Guix, extra dependencies can be added by instead running @command{guix
+environment} with @option{--ad-hoc}:
 
 @example
 guix environment guix --pure --ad-hoc help2man git strace
@@ -113,8 +115,8 @@ run @code{make install}.  To do that, you first need to have an environment
 with all the dependencies available (@pxref{Building from Git}), and then
 simply prefix each command with
 @command{./pre-inst-env} (the @file{pre-inst-env} script lives in the
-top build tree of Guix; it is generated by @command{./configure}),
-as in@footnote{The @option{-E} flag to
+top build tree of Guix; it is generated by @command{./configure}).
+An example@footnote{The @option{-E} flag to
 @command{sudo} guarantees that @code{GUILE_LOAD_PATH} is correctly set
 such that @command{guix-daemon} and the tools it uses can find the Guile
 modules they need.}:
@@ -125,7 +127,7 @@ $ ./pre-inst-env guix build hello
 @end example
 
 @noindent
-Similarly, for a Guile session using the Guix modules:
+Similarly, an example for a Guile session using the Guix modules:
 
 @example
 $ ./pre-inst-env guile -c '(use-modules (guix utils)) (pk (%current-system))'